Generally speaking, the backlight module is classified into a direct type backlight module or an edge-lit type backlight module based on its light source position. The light source of the direct type backlight module is disposed right below the backlight module, and the direct type backlight module is usually applied to large size LCDs. On the other hand, the light source of the edge-lit type backlight module is disposed on the lateral sides of the backlight module, and the edge-lit type backlight module is usually applied to small size LCDs. However, when the size of the panel becomes lager and lager, such as liquid crystal TV display panels, the dimension and weight of the back plate for supporting backlight modules is also become larger. In order to increase the bending strength, the lateral side of the back plate is made into an N shape, or the thickness of the back plate is increased. Therefore, the total weight of the backlight module and the liquid crystal TV is increased.
As shown in FIG. 1, it is a perspective view of a conventional back plate. Please refer to FIG. 2 and FIG. 3 together. FIG. 2 and FIG. 3 are side views of a conventional back plate. A back plate 9 comprises a supporting portion 910 connected with a first vertical wall 920 to form an accommodation space; a horizontal wall 930 connected between the first vertical wall 920 and the second vertical wall 940. The first vertical wall 920, the horizontal wall 930, and the second vertical wall 940 are formed into an N shape.
As shown in FIG. 2, when an external force is applied to the second vertical wall 940, the second vertical wall 940 is bent inward and deformed (the dot line 960 in FIG. 2).
As shown in FIG. 3, when the size of the panel is large, the area of the corresponding back plate 9 has also become large; however, if the bending strength of the supporting portion 910 doesn't increase correspondingly, the supporting portion 910 may be bent inward and deformed (the dot line 950 shown in FIG. 2) once the supporting portion 910 is pressed inward by an external force.
Therefore, it is required to provide a back plate structure, which will not deformed, to which an external force is applied, so as to solve the above mentioned problem.